The present invention relates to the field of earthmoving machines. Specifically, the present invention discloses a bail for a mining shovel.
A conventional rope mining shovel includes a boom, a handle moveably coupled to the boom, a dipper that is coupled to a handle, a bail that is coupled to the dipper, an equalizer that is coupled to a top portion of the bail, and a hoist rope that is coupled to the equalizer. The hoist rope passes over a boom sheave coupled to an end of the boom, and is reeled in and paid out by a hoist drum. The bail provides a rotating connection between the ropes and the dipper, and maintains clearance between the rope and both the dipper and the material in the dipper. The equalizer aligns the hoist rope to be tangent to the boom sheave, reducing wear on the rope.
In general, there are three conventional methods to attach hoist rope to a dipper body supported on a rope shovel. First, a dipper including an equalizer integrally-formed with the dipper increases dump and dig heights at the expense of reduced cutting and dig forces. Alternatively, a dipper including a bail with integral rope mounting blocks improves cutting forces. This configuration compromises rope life, however, due to bending of the ropes at the bail connection when the bail rotates forward while the ropes are slack. Third, a dipper including both an equalizer and a bail provides increased cutting forces and an additional pivot point to keep the hoist ropes aligned, but the combination decreases dig and dump heights. As a result, all of the known configurations have a disadvantage with respect to one of these factors (dig/dump heights, cutting force, and rope wear rate).